Coincidentally, I'm reworking the embedded player portions of TubePress right now. My primary goal is to make it easier to (programatically) add embedded player options, and the YouTube iframe player is my guinea pig. The code is not in production state yet, and will likely not be particularly easy to hack into TubePress 2.1.2 as there were some significant architectural changes that went along with this. But the good news, I suppose, is that the feature is well on its way to being implemented and will definitely be included in the next release of TubePress.

I don't know too much about YT3D - interesting. I'm mostly interested in using the iframe to allow for easier video playback on mobile devices.